Infantile tremor syndrome (ITS) is defined by the tetrad of pallor, developmental delay/regression, skin pigmentation, and brown scanty scalp hair. Involuntary movements in the form of tremors supervene in the natural course of the illness in a significant number of cases. The disorder occurs in exclusively breast-fed infants of vegetarian mothers belonging to economically deprived sections of society. Most of the children eventually recover but are frequently left with long-term cognitive and language neurodeficits. ITS continues to be seen in clinical practice, but there has been no consensus on its causation. Last comprehensive review was published in 1987 describing the ITS as a syndrome of unknown or multiple etiologies. Several important papers have been published since then. This review attempts to provide comprehensive and up-to-date information on the subject incorporating recently published studies. In the end, the issue of etiology is objectively re-examined in the light of available evidence some of which has been published in recent years.